Andy Goldsworthy is an enviromental/nature sculptor creates sculptures that are often fleeting. His sculptures really embodies the exploration of art and line in nature. He has amazing vision. I recommend his books and videos of his work. The ones that show him working are especially great. Be inspired by him to look more closely around you for drawing or nature inspiration (even if you are not an artist!).
When drawing or sketching outside look for those lines or paths created in nature visually. They are there, just look closely. Make it a goal when looking for drawing inspiration to find something you have never noticed before, even if it is very small!
To get you started with inspiration check out this youtube of Andy Goldsworthy creating and notice the “lines” of ice in space he makes. https://youtu.be/f7sZv4_0Fxg Also to see the full film on this Netflix has it. It is titled “Rivers and Tides”. Enjoy the visual journey!